Impact of Margin Assessment Method on Positive Margin Rate and Total Volume Excised

Background

For breast-conserving surgery, the method of margin assessment that most frequently achieves negative margins without increasing the volume of tissue excised is uncertain. We examined our institutional experience with three different margin assessment methods used by six experienced breast surgeons.

Methods

Patients undergoing breast-conserving surgery for invasive carcinoma during July to December of a representative year during which each method was performed (perpendicular, 2003; tangential, 2004; cavity shave, 2011) were included. The effect of margin method on the positive margin rate at first excision and the total volume excised to achieve negative margins were evaluated by multivariable analysis, by surgeon, and by tumor size and presence of extensive intraductal component (EIC).

Results

A total of 555 patients were identified, as follows: perpendicular, 140; tangential, 124; and cavity shave, 291. The tangential method had a higher rate of positive margins at first excision than the perpendicular and cavity-shave methods (49, 15, 11 %, respectively; p < 0.0001). Median volumes to achieve negative margins were similar (55 ml perpendicular; 64 ml tangential; 62 ml cavity shave; p = 0.24). Four of six surgeons had the lowest rate of positive margins with the cavity-shave method, which was significant when compared to the tangential method (p < 0.0001) but not the perpendicular method (p = 0.37). The volume excised by the three methods varied by surgeon (p < 0.0001). The perpendicular method was optimal for T1 tumors without EIC; the cavity-shave method tended to be superior for T2–T3 tumors and/or EIC.

Conclusions

Although the cavity-shave method may decrease the rates of positive margins, its effect on volume is variable among surgeons and may result in an increase in the total volume excised for some surgeons and for small tumors without EIC.     

Laparoscopic versus open peritoneal dialysis catheter insertion cost analysis

Background

Peritoneal dialysis (PD) is a cost-effective alternative to hemodialysis (HD). PD catheters have traditionally been inserted through a small open incision, but insertion using laparoscopic visualization has become increasingly popular and is associated with less catheter malfunction. The aim of this study was to compare costs of laparoscopic and open insertion strategies while taking into account postoperative complications and future salvage procedures.

Methods

A decision analysis model was constructed to simulate 1 y outcomes after PD catheter insertion by either the open or laparoscopic approach. Possible outcomes after PD catheter placement included functional catheter, infection, and catheter malfunction. Ultimately, patients continued with successful PD or switched to HD. Baseline probabilities, costs, and ranges were determined from a critical review of the literature. Sensitivity analyses were performed to determine the model strength over a range of clinically relevant probabilities.

Results

The total annual costs, including postoperative management and dialysis treatment, were $69,491 for laparoscopic insertion and $69,960 for open insertion. In case of a catheter malfunction, an initial attempt at salvage by fluoroscopy-guided wire manipulation cost less than a first attempt by laparoscopic repositioning.

Conclusions

When accounting for a year of postoperative management and treatment, laparoscopic insertion can be less costly than open insertion in the hands of an experienced surgeon. Despite higher initial costs, PD catheter insertion under laparoscopic visualization can have lower total costs due to fewer postoperative complications. With increasing emphasis on cost-effective care, laparoscopic insertion is a valuable tool for initiating PD.     

Fluorescent-tilmanocept for tumor margin analysis in the mouse model

Background

Dendritic cells (DC) are localized in close proximity to cancer cells in many well-known tumors, and thus maybe a useful target for tumor margin assessment.

Materials and methods

[^99mTc]- cyanine 7 (Cy7)-tilmanocept was synthesized and in vitro binding assays to bone marrow-derived DC were performed. Fifteen mice, implanted with either 4T1 mouse mammary or K1735 mouse melanoma tumors, were administered 1.0 nmol of [^99mTc]-Cy7-tilmanocept via tail vein injection. After fluorescence imaging 1 or 2 h after injection, the tumor, muscle, and blood were assayed for radioactivity to calculate percent-injected dose. Digital images of the tumors after immunohistochemical staining for DC were analyzed to determine DC density.

Results

In vitro binding demonstrated subnanomolar affinity of [^99mTc]-Cy7-tilmanocept to DC (K_A = 0.31 ± 0.11 nM). After administration of [^99mTc]-Cy7-tilmanocept, fluorescence imaging showed a 5.5-fold increase in tumor signal as compared with preinjection images and a 3.3-fold difference in fluorescence activity when comparing the tumor with the surgical bed after tumor excision. Immunohistochemical staining analysis demonstrated that DC density positively correlated with tumor percent of injected dose per gram (r = 0.672, P = 0.03), and higher DC density was observed at the periphery versus center of the tumor (186 ± 54 K versus 64 ± 16 K arbitrary units, P = 0.001).

Conclusions

[^99mTc]-Cy7-tilmanocept exhibits in vitro and in vivo tumor-specific binding to DC and maybe useful as a tumor margin targeting agent.     

Genetic Biomarkers in Epilepsy

The identification of valid biomarkers for outcome prediction of diseases and improvement of drug response, as well as avoidance of side effects is an emerging field of interest in medicine. The concept of individualized therapy is becoming increasingly important in the treatment of patients with epilepsy, as predictive markers for disease prognosis and treatment outcome are still limited. Currently, the clinical decision process for selection of an antiepileptic drug (AED) is predominately based on the patient’s epileptic syndrome and side effect profiles of the AEDs, but not on effectiveness data. Although standard dosages of AEDs are used, supplemented, in part, by therapeutic monitoring, the response of an individual patient to a specific AED is generally unpredictable, and the standard care of patients in antiepileptic treatment is more or less based on trial and error. Therefore, there is an urgent need for valid predictive biomarkers to guide patient-tailored individualized treatment strategies in epilepsy, a research area that is still in its infancy. This review focuses on genomic factors as part of an individual concept for AED therapy summarizing examples that influence the prognosis of the disease and the response to AEDs, including side effects.